A vehicular seat is required to be adapted to the provision of an inner projection in European automobile standards ECE No. 21 to protect passengers in a back seat. According to the provision of the inner projection, all projections that may collide with a passenger's head are required such that a terminal portion of a distal end thereof is formed to have an R chamfered shape with a radius of 3.2 mm or more. In a headrest stay of a vehicular seat disclosed in JP-A-H09(1997)-086250, a terminal portion of a distal end of a headrest stay is subjected to a spinning process or a swaging process to have an R chamfered shape with a radius of 5 mm or more.
In the related art JP-A-H09(1997)-086250, the terminal portion of the distal end of the headrest stay is subjected to the spinning process or the swaging process. However, the related art is problematic in that both the spinning process and the swaging process push a ladle-shaped part from a direction perpendicular to a rotating axis while imparting rotation to the headrest stay, so that R is small and thereby cracks may undesirably occur if the headrest stay is shaped to have a high tightening force.